The lower South Island, including Dunedin, was shaken by a strong earthquake last night.

Geonet reported the quake as magnitude 6.4 and says it occurred 190km southwest of Snares Island, below Stewart Island, at a depth of 34km.

Civil Defence says there was no tsunami threat from the quake.

The quake was felt widely across the South, including in Invercargill, Tapanui, Wanaka, Outram, Mosgiel and Dunedin.

A Fire and Emergency New Zealand spokesman says he had contacted firefighters in Invercargill after the earthquake and there were no reports of damage.

And a police spokeswoman says police had no reports of any earthquake-related damage in the South.